Biconical high-frequency antenna



Feb. 13, 1951 G. G. GREENE 2,541,870

BICONICAL HIGH-FREQUENCY ANTENNA Filed July 16, 1948 UNITED STATESPATENT OFFICE a I I B ICONI CAL HIGH-FREQUENCY ANTENNA 1 Gardiner G.Greene, Newton, Mass., assignor to The Workshop Associates,Incorporated; New- .ton Highlands, Mass a corporation of Massa-f 7 Fret- Q l lfl'i l '1'Application'July'lfi,1948, serialNmsemli; g

zclaims; (01.250-33) Antennas for receiving high frequency telethin foilsuch as aluminum, copper orother con- Yision and frequency modulationsignals are genducting material covers the outside of each o erallyeither "of'the-half wave dipole type or a the triangular pieces. simplevarray comprising a dipole and a reflector To increase the mechanicalstrength and rigidmounted at as greata heightabove the ground ity of pthe pyramidal structure, a poly Onally as possible. To obtain an optimumsignal to shaped stiffening member, having a number of noise'pratio andto eliminate reflected signals, sides which corresponds withthe numberof trisuch antennas 'must be carefully tuned, and angular pieces in thepyramidal structure, is ino'rientedafter: installation, an operationrequiring serted within the structure with each of its sides theservices 'ofxa skilledmechanicbecause of the 10 abutting theinner-surface of a'respective triancriticalness of such adjustments andthe height gular piece; An ea-r projects from each respective above theground-at which such adjustments are side of the polygonal memberthrough a correnecessarily made: Being tu'nedto a single wave spendinaperture in he; abutting trian ular length, such antennas of the dipoletype inher piece to fasten the polygonal member in position ently givepoorer-performance on. all other wave within the. structure. The apex ofthe structure lengths so that it is often necessary to use sev-' isstrengthened by a. conductingmember having eral-such"-"antennas to coverthe television frea plurality of arms each-of which is attached toquency bands In order to avoid some of these dis the apex of arespectivetriangular piece thereby advantages-,th'e use of wide bandantennas of insuring the electrical interconnection of thethezhorntype,hasjbeen proposed but-these sysgo foils. I w temsthaveheretoforebeen quiteheavy, difficult to A'further feature of theinvention is a conconstruct and install, and expensive. nectingmembervvhich may be a rod of insulating material with one end projectingthrough two holes located on the axis-of the pyramidal structure in thepolygonally shaped member and :the

Objects of this invention are to provide a high frequency antenna of thebiconical type which maintains a good impedance match to thetransmission line over a'wide frequencyband, which conducting memb r rsp c v ly e pp si e is easily adjusted and oriented, which-can be inendof the connecting member'p qj through stalled indoors; which can beassembled and consimilarly located holes in the polygonally shapednected without special tools or skill, which is light and conductingmemb of a Second py dal in weight, which is inexpensive to construct,and tructure t reby o m i ta n th se S ructures which advances the artof antenna manufacture in axial al nm t'with th ap x s th r of ingenerally. spaced relationship. -'i:iInTa broad aspect the inventioncontemplates a se a d ot e j c s andasp c s Of t e in;

high frequency antenna comprising a pyramidal vention will be app from pfi m structure of insulating material with oneside 1106111116111? t f ll'IIa Wd l -1 8 d a f i 1 thereof covered by a-conductingfoil. Thethickwhich ness of the foil is small relatively to the thickness Fig. 1is arr-isometric I view of such embod i-:- of the insulating material sothat the foil is supment; a ported thereby. In ;another aspect two suchFig. 2 is a plan view-of-two adjacent triangular pyramidal structuresare maintained in axial '40 pieces showing one method ofinterlockingthem;

alignment with the apexes thereof in spaced re- Fig. ;-3 isanenlargedfragmentary cross sec- 7 lationship by a "connecting member ofinsulating tional view on line 3-3 of Fig-. 1; v I material. v v 4 lFig. 4- is an elevation of the conducting meme In a specific aspect thepyramidal antenna her; and v structure comprises a plurality oftriangular Fig. 5 is'a partial elevation ofthe polygonally pieces ofinsulating material for example fiber shaped stiffening member.

board or plywood; A plurality of tabs project "In Fig. ,1 are shown;-two identical pyramidal from each of two respective sides ofeachtriansupporting structures II with their axes in her-i; ular p ece-Eac sta has a fin erpr i g zontalalignmentzand .the pex he efi sparnormally therefrom which is formed by a slot relationship. 3 Each of thestructures It co n;- havingna side inralignment with the edge of theprises eight triangular pieces I2; of light Weight triangularpiece-supporting thetab. Each slot insulating material-{for examplecorrugated fiber and finger engage a corresponding finger and slotboard, positioned with their respective edges respectively on theadjacent edge of another of abutting to form aneight sided hollowpyramid said pieces,tnerebxiteeomp e -the; tr tu l; A wi h an penabasa.As i sh wnz n Fi .1.; .39.2.

outside of each triangular piece i2 is covered with a conducting foil[5, for example aluminum, the thickness of which is small relatively tothe thickness of the fiber board so that the foil is supported thereby.

Two edges of each respective piece l2 are each provided with three tabs:l3 which interlock with the respective corresponding tabs on theabutting edges of the corresponding adjacent pieces. As is shown indetail in Fig. 2 each tab I3 includes a finger l4 projecting normallytherefrom parallel to the adjacent edge of the piece [2. Each finger I4is formed by a slot 16 one side of which is in alignment with the edgeof the piece l2 sup-- porting the tab l3. The fingers on the respectiveedges of each piece [2 point in opposite directions. Two adjacent piecesl2 are interlocked by engaging the fingers M and the slots l6 of onepiece [2 in the corresponding slots and fingers of the adjacent piece.

It is also possible to point the fingers IL on both edges of one piece i2 in the same direction. When this is done the fingers [4 on both edgesof each piece [2 must point in the opposite direction, the" fingers onadjacent pieces being directed in opposite directions. Although theabove described methods of interlockin are preferred because of itssimplicity and the ease or assembly, it is also possible to connect thepiecess l2 b other well-known means, for example, staples, gummed tapeor any of the various types of interlocking tabs or cars. I The apexesof the interlocked pieces l2 are fastened together by a metal conductingmember I! which is inserted inside the pyramidal structure H. As isshown in Figs. 3 and 4, the conducting member I! has a plurality of armsI8 each of which is fastened to a respective triangular piece I! byaself tappin screw (9. The screws l9 project through holes. 2| (Fig. 2)near the apex of each of the triangular pieces 12 to engage the holes22' in the respective arms I 8. A washer 23 is placed under the head ofeach screw Is to make contact with the foil I on each of the respectivetriangular pieces [2 to insure electrical interconnection of all thefoils through the conducting member [1.

Further to reinforce the pyramidal structure II, a polygonally shapedstiffening member 24 of insulating material is inserted therein so thatan ear 26 (Fig. 5) on each of the respective sides thereof projectsthrough an aperture such as the slot 21 in each respective abuttingtriangular piece 12.

The pyramidal structures H are maintained in axial alignment with theirapexes in spaced relationship by a connecting member of insulatingmaterial such as the wooden rod 28. One end of the rod rojects throughthe holes 29 and 3| axially located in the polygonal member and theconducting member respectively of one pyramidal structure H. Theopposite end of the rods engage similarly located holes in the otherpyramidal structure. A plastic collar 30 is attached at the center pointof the rod 28 so that the apexes of the respective pyramidal structuresl I cannot make electrical contact with each other.

" The antenna is located indoors at as great a height above the groundas practicable, for example, in an attic or under the roof of a garage.Assembly is preferably performed at the final location by laying out thetriangular pieces l2 upon the floor with the foil t5 downwardly and theninterlocking the adjacent pieces [2 by slid- 4 ing therespective fingersI4 and slots l6 into engagement as described above.

Before completing the final joint, the assembly should be lifted andformed into the eight sided pyramidal structure H with the apex thereofdownward and the foil [5 on the outside. With the apex of the structureH resting upon the fioor, the cats 26 of the polygonal shapedreinforcing member are then inserted in the respective slots 21 in thetriangular pieces I2.

The structure H is next turned over so that its base rests upon thefloor and the conductirig member I! inserted inside the apex of thestructure II and rotated so that the holes 22 in the arms l8 thereof arein alignment with the respective holes in the triangular pieces l2. Theconducting member i1 is secured in this position by inserting one of thescrews IS in each of respective pair of aligned holes. Before insertineach screw is a washer 23 is placed under the head thereof.

The second pyramidal structure it is assembled in a similar manner. Tomaintain the structures H in horizontal axial alignment the ends of theconnecting rod 28 are inserted in the holes 29 and 3| of the respectivepolygonal stiffener and star shaped conducting member of the structuresll. Each of the wires of the lead-in cable 32 is clipped under arespective screw 19 in the apex of each of the pyramidal structures H.

When thus assembled the antenna is ready for use. Adjustment to give amaximum per'-. formance of the receiver is made by rotating the assemblyabout a vertical line through the colla 30 of the'rod 28.

Under some conditions most satisfactory results may be obtained by theuse of a reflector such as indicated at 33 of Fig. 1, comprising a sheetof conducting foil, similar tothe covering foil [5, hung in a verticalplane parellel to and located approximately 3 /2 feet from thehorizontal axis or the structures H. This distance is varied to obtainthe optimum location where the best results without double images areob-' tained. In some cases double images may be eliminated by rotatingstructures I I so that there is, a small angle between the axis thereofand the plane of the reflector 33.

It should be understood that the present disclosure is for the purposeof illustration only and that this invention includes all modificationsand equivalents which fall within the scope of the appended claims.

I claim:

1. A high frequency antenna comprising a plurality of triangular piecesof insulating material each with an aperture therein, a plurality oftabs projecting from each of two respective edges of said pieces, eachtab having a finger projecting normally therefrom, said finger beingformed by a slot having one side in alignment with the edge of thetriangular piece supporting the tab, said slot and finger engaging thecorresponding finger and slot respectively of the edge of another ofsaid pieces thereby to com plete a pyramidal supporting structure, athin conducting foil covering the outside of each of the respectivetriangular pieces, a polygonally shaped stiffening memberof insulatingmaterial with an ear projecting from each of the respec tive sidesthereof to engage apertures in adjacent triangular pieces, and aconducting member having a lurality of arms each of which is fas i tenedto the apex of one of the respective'trian 5 gular pieces therebyinsuring electrical interconnection of said foils.

2. A high frequency antenna comprising two pyramidal structures eachincluding a plurality of separate triangular pieces of insulatingmaterial, each piece having an aperture therein and a plurality of tabsprojecting from each of two ger projecting normally therefrom, saidfinger being formed by a slot which has a side in alignment with theedge of the triangular piece supporting the tab, and each of said slotsand fingers engaging the corresponding fingers and slots respectively onthe adjacent edge of another of said pieces thereby to complete saidstructure; a thin conducting foil covering the outside of each of therespective triangular pieces; a polygonally shaped stiffening member ofinsulating material having a hole in the center thereof and an earprojecting from each of the respective sides thereof to engage theapertures in adjacent triangular pieces; a conducting member having ahole in the center thereof and a plurality of arms each of which isfastened to the apex of a respective triangular piece thererespectiveedges thereof, each tab having a fin- 7 byvinsuring electricalinterconnection of said ;;foils; and a connecting rod of insulatingmate-- rial having one end projecting through the respective holes insaid connecting member and isa-id'fpolygonal member of one of saidstructures, fthejother rod end projecting through the respective holesin said conducting member and j -polygonal member of the other of saidstrucwares thereby to maintain the apexes of said 10 ;lstructures inaxial alignment and spaced relationship.

GARDINER G GREENE.

REFERENCES CITED The following references are of record in the UNITEDSTATES PATENTS Num er Name Date 1 ,061,297 Johnson May 13, 1913 1,959104 Ewers Mar. 6, 1934 2,267,889 Aubert Dec. 80. 1941 w 2,440,597 AtwoodApr. 27, 1948 2352.822 Wolf Nov. 2. 1948'

